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Hmm, well you can cast pointers to other types but that doesn't change what the
pointer really points to. Just because the compiler lets you do it doesn't make it right.
The fact that you needed a cast should always be a warning sign.
Maybe back up a bit - what are you wanting or trying to do?
Mark
Mark Salsbery
Microsoft MVP - Visual C++
![Java | [Coffee]](https://codeproject.freetls.fastly.net/script/Forums/Images/coffee.gif)
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My basic problem is to understand how to access the runtime class using the CRuntimeClass structure.
I'll go back to books for now.
Thanks Vaclav
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Vaclav_Sal wrote: My basic problem is to understand how to access the runtime class
I'm not convinced. I think your basic problem is you don't know "why" you think you need to access the runtime class. I think you are assuming you need to access the runtime class. You may be right, you may be wrong, I don't know.
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Here's a good place to start: CRuntimeClass Structure[^]
Maybe led mike linked to that as well - I'm too lazy to click his links 
Mark Salsbery
Microsoft MVP - Visual C++
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My initial reaction to your post is WTF?
You don't appear to have a proper understanding of CRuntimeClass.
Also....
Vaclav_Sal wrote: This code shows "normal " CRuntimeClass members of class CMyTabView.
What does "This code shows" mean?
Vaclav_Sal wrote: And this one has same pointer and show the CMyTabView class
again with the "show". Are you talking about viewing the pointer in the debugger? If so you don't appear to understand what "casting" is and how the debugger "watch" feature works. If you tell it a "foo" is a "bar" then it's going to show you the structure of a "bar" object in memory because that's what you told it to do when you "cast" it. It doesn't mean that the pointer actually points to a "bar" structure in memory.
Seems to me you need to do study casting a while longer until you understand it more completely. Perhaps you could start here[^].
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Well my initial reaction was - thanks for nothing!
Would I ask these questions if I fully understood the subject of CRuntimeClass?
I do appreciate the link, thanks.
Vaclav
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They maybe are sometimes a bit rude, but usually the "nothing" answers have helpfull information too. Just need to re read and analize without "offended feeling" (at least that's what I try when I get a "rude" answer)
Greetings.
--------
M.D.V. 
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson
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Nelek, your comments are appreciated.
I am well aware that everybody is different.
I don't think Led Mike was rude. I am just not impressed by his "WTF" remark as his first reaction and than him restating the obvious that I did not know the subject well. His link was constructive suggestion and appreciated.
PS The “mystery” of utilizing RUNTIME_CLASS macro is almost solved thanks to everybody input.
Cheers
Vaclav
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Hi,
I'm reposting my problem with vertical scroling since no one is replaying eany more on my first thread.
So what I want is wnen I use mouse wheel to get scrolling faster, so upon sugetion from Nelek I'm doing this:
<br />
BOOL CMyView::OnMouseWheel(UINT nFlags, short zDelta, CPoint pt)<br />
{<br />
int pos =GetScrollPos( SB_VERT );<br />
if (zDelta>0)<br />
OnVScroll(3*SB_LINEUP,pos,NULL);<br />
else if (zDelta<0)<br />
OnVScroll(3*SB_LINEDOWN,pos,NULL);<br />
return TRUE;<br />
}<br />
When I scroll by LINEDOWN it's OK, but when I do the oposite (SB_LINEUP) it has no effect, scrolling it slow again.
Why?
Thanks!
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I don't know why, but have you tried with -3 * SB_LINEDOWN ??
Have you checked if SB_LINEDOWN == - SB_LINEUP ?
Mappng mode, one direction must be the different sign of the other
Greetings.
--------
M.D.V.
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson
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What are you doing, man?
josip cagalj wrote: if (zDelta>0)
OnVScroll(3*SB_LINEUP,pos,NULL);
else if (zDelta<0)
OnVScroll(3*SB_LINEDOWN,pos,NULL);
Since (see winuser.h)
...
#define SB_LINEUP 0
#define SB_LINELEFT 0
#define SB_LINEDOWN 1
#define SB_LINERIGHT 1
#define SB_PAGEUP 2
#define SB_PAGELEFT 2
#define SB_PAGEDOWN 3
...
3*SB_LINEUP evaluates to SB_LINEUP itself.
while
SB_LINEDOWN evaluates to SB_PAGEDOWN.
Moving the wheel, you scroll a line up, a page down.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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He wants to increase the speed on scrolling.
BTW, I thought the working area is 10 pages and 100 lines.
Quote from VC++ help:
You specify the amounts to scroll horizontally and vertically in logical units. By default, if the user clicks a scroll bar shaft outside of the scroll box, CScrollView scrolls a “page.” If the user clicks a scroll arrow at either end of a scroll bar, CScrollView scrolls a “line.” By default, a page is 1/10 of the total size of the view; a line is 1/10 of the page size. Override these default values by passing custom sizes in the SetScrollSizes member function. For example, you might set the horizontal size to some fraction of the width of the total size and the vertical size to the height of a line in the current font.
And winuser.h it says that page = 3*line...
Can you explain a bit more about? Because I am the one who told him to use the X*SB_PAGEUP/DOWN the other day. And now is a bit conusing for me too.
Greetings.
--------
M.D.V.
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson
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Nelek wrote: Override these default values by passing custom sizes in the SetScrollSizes member function
I think the above is the right approach.
On the other hand, the OP is hacking the nSBCode argument (of the method OnVScroll) that is just (MSDN):
a scroll-bar code that indicates the user's scrolling request.
i.e. a qualitative parameter rather than a quantitative one (like the amount of requested scroll).
Hope that helps
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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CPallini wrote: Nelek wrote:
Override these default values by passing custom sizes in the SetScrollSizes member function
I think the above is the right approach.
It depends on many things. I used this quantitative solution insteads of overriding the SetScrollSizes because my boss wanted UP/DOWN keys to scroll accuratelly and the wheel to do it faster but not changing a page that must stay as it was with PageUp/Down.
I finally used that N*SB_LINEUP/DOWN actually I used +-N*SB_LINEDOWN for the wheel to make it 3 times faster than keys or bar-arrow-clicks as he wanted.
And, as it worked fine for me (work right doesn't mean to be right, I know), I gave that option to him as well. Is there any way to do it just with "qualitative" parameter? Because I found no "fourth" messure to scroll a view. Just these 3: sizeTotal, sizePage, sizeLine...
VC++ 6.0
How can I solve that issue in a correct way?
Greetings.
--------
M.D.V.
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson
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Nelek wrote: +-N*SB_LINEDOWN
-N*SB_LINEDOWN (with N>0) should be meaningless to standard OnVScroll.
Even overriding OnVScroll to re-intepreter its first parameter doesn't seem to me a good design choice.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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Aham,
then... how should I make to have a 3-speed scrolling as I explained but in a good structure? Line with arrow keys, middle with Wheel and Page with pageup/down keys or out the little bar at the scrollbar.
Greetings.
--------
M.D.V.
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson
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Well a quite rude, but simple solution maybe issuing three times the call to OnVScroll (PostMessage ?) with either SB_LINEDOWN or SB_LINEUP.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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Nelek wrote: I actually thought on that, but I figured that it would be worst than the other solution.
Don't change it just because I told about: before you have to find my points valid.
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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Once again thank you both for yours participation on this thread!
You helped me indeed.
If I realy did call pageup it suit's me. It's my fault for not checking this option before. I thought pageup/down would be big for my needs, but this is ok!
P.S.
For Nelek: pageup/down doesn't scroll a whole page (at least not in my case), I mesured when I do scroll(using mouse wheel) it takes 11 scroll lines (up/down keys)to go back at start position.
P.P.S.
my setscrollsize:
SetScrollSizes( MM_TEXT, CSize(m_nMaxX+30, m_nMaxY+90));
where m_nMaxX and m_nMaxY are from my Client rectangle!
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With the term page I didn't mean a whole page. Read another time:
1 TotalSize = 10 Pages;
1 Page = 10 Lines;
NOTE: If you dont say anything else this is standard behaviour.
Just a question... why do u set Scroll size bigger than client area?
I.E. One DIN A-4 = 210 * 297 mm (Standard-printable-area 190 * 280 mm)
to have a ratio 5 Pixels : 1 mm in my app I used
CSize sizeTotal;
sizeTotal.cx = 950; sizeTotal.cy = 1400; //190*5 and 280*5
SetScrollSizes(MM_TEXT, sizeTotal);
Greetings.
--------
M.D.V. 
If something has a solution... Why do we have to worry about?. If it has no solution... For what reason do we have to worry about?
Help me to understand what I'm saying, and I'll explain it better to you
“The First Rule of Program Optimization: Don't do it. The Second Rule of Program Optimization (for experts only!): Don't do it yet.” - Michael A. Jackson
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Nelek wrote: Just a question... why do u set Scroll size bigger than client area?
I use bigger scroll size because I'm placing some object's on backplane(MyView) and on my last placing I wont to enlarge my page so I can make place if user wont's to add more objects!
MyView(CFormView) is some kind of help for me because on the end I'm doing some coding (collect positions and relasionships betwen objects and then presenting it as something else....) my stuff, dont want to dother anyone with this...
Thanks everybody for their effort
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Given a char c and an int i,
is there any difference between casting the int to the char: c = (char)i;
and just assigning it: c = i;
many thanks
Tzumer
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Someone already answered that yesterday.
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The result is the same.
However, (depending on the warning level set), in the latter case, i.e.
e.tzumer wrote: just assigning it: c = i;
the compiler may emit the following warning:
conversion from 'int' to 'char', possible loss of data
If the Lord God Almighty had consulted me before embarking upon the Creation, I would have recommended something simpler.
-- Alfonso the Wise, 13th Century King of Castile.
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